1. Field
The field of the invention is toy airplanes and more particularly such airplanes which are adapted to automatically execute maneuvers after launch into free flight.
2. State of the Art
Among free flight, unpowered airplanes, those hand launched probably pre-date all other types, toy or otherwise, and range from simple folded paper gliders to those capable of more complex maneuvers. Most have employed fixed airfoil geometry, selected to cause the plane to execute somewhat predictable maneuvers such as climbs, banking turns, and even loops. Some have been launched into free flight by impetus directly from the user's hand, while others have utilized catapulting devices, such as tensioned elastic bands. Maneuvers typically begin in the immediate vicinity of the operator, and often return the plane to his vicinity. Some planes are launched at high velocity, and are heavy enough to injure the operator. Some prior art planes provide for airfoil geometry change during flight, induced by air resistance. Hinged tail plane elevators have been utilized, urged toward raised positions by tension springs. At launch, the elevators are quickly snapped into lowered position by high drag. Thereafter, elevator drag decreases with decreasing airplane velocity, the elevators rising to impart upward pitching forces resulting in looping maneuvers. Spring tension is maximum while projected drag area is minimum, so that the geometry of the system is necessarily unstable. The elevators tend to snap unpredictably back into raised position. To assure that the loop occurs remote from the operator, quite high launch velocity is necessary. For a toy, the necessary precision of construction, the required strength and weight, and the demanding carefulness in use are excessive. Cost is unnecessarily high, and performance remains unpredictable.